Detergent compositions in tablet form are known in the art, as discussed below, and some products are now on the market. Tablets have several advantages over powdered products: they do not require measuring and are thus easier to handle and dispense into the washload, and they are more compact, hence facilitating more economical storage.
Detergent tablets are described, for example, in GB 911204 (Unilever), U.S. Pat. No. 3,953,350 (Kao), JP 60-015500A (Lion), JP 60-135497A (Lion) and JP 60-135498A (Lion); and are sold commercially in Spain.
Detergent tablets are generally made by compressing or compacting a detergent powder.
As pointed out in EP-A-522766 (Unilever), difficulty has been encountered in providing tablets which have adequate strength when dry, yet dispense and dissolve quickly when wet.
EP-A-522766 discloses tablets of compacted particulate detergent composition in which at least some particles of the composition are individually coated with a material which functions as a binder but also functions as a disintegrant capable, when the tablet is immersed in water, of disrupting the structure of the tablet. At least some of the binder/disintegrant materials disclosed are able to melt at temperatures which are above ambient but below 90.degree. C.